Self-acting tap-head



2 Sheets-Sheet 1.

Patented May 2, 1893.

Mw M (www Arron/ver'. v

S. D.`LELAND. SELF ACTING TAP HEAD.

"ist

(No Model.)

(No Model.)

2. .fu e e h S e e h s 2 D# ,.m DH NP AA LT H G Lm .m DA F S.L E SPatented May 2, 1893.

FILLE. Flmu. m5,".

mha.

WHA/5885s'.- EW/.Unwinmoms/Erf;

UNITED STATES PATENT Orifice.,

SANFORD D. LELAND, OF H OLYOKF., MASSACHUSETTS.

SELF-ACTING TAP-,H EAD.

SPECIFICATION forming part of Letters Patent No. 496,420, dated May 2,1893.

Application iiled April 2, 1892. Serial No. 427.481. (No model.) I

To all whom t may concern:

- Be it known that I, SANFORD D. LELAND, of Holyoke, in the county ofHampden and State of Massachusetts, have invented a new and usefulImprovement in Self Acting Tap- Heads, of which the following is aspecification, reference being had to 'the accompanying drawings,forming part thereof.

In Letters Patent of the United States No. 393,511, issued to me on the27th day of November, A. D. 1888, I have shown, described and claimed aself-actingtap-head comprising a friction clutch by means of which arevolving movement is transmitted from a revolving spindle to the tap,and automatic releasing devices for rendering said clutch inoperative toturn the tap, as the latter approaches the bottom of the hole withinwhich it is working.

The .object of my present invention is to improve the construction ofsaid tap-head by reducing the number of parts, thereby lessening itscost, and by providing it with a positive clutch mechanism in lieu ofthe friction clutch therein utilized.

To these ends my invention consists in the tap-head constructed andoperating as hereinafter fully described and particularly pointed out inthe claims.

Referring to the drawings, in which like parts are designated by likeletters and numerals in the several figures, Figure 1 is a centralvertical section of the tap-head. Fig. 2 is a side elevation of theupper member and a vertical section of the lower member, the same beingshown revolved one-fourth of a revolution from the position shown inFig. 1. Fig. 3 is a side elevation,partly in section, illustrating themanner of withdrawing the tap by reversing the movement thereof. Fig. 4.is a cross-section taken upon line 2 2 of Fig. 2. Fig. 5 is a plan ofthe upper end of the upper member of the device. Fig. Gis a sideelevation of said upper member. Fig. 7 is acrosssection thereof, takenupon line o-o of Fig. 6. Fig. 8is a side elevation of the lower memberofthe head. Fig. 9 is a cross-section thereof taken upon line oc-oc ofFig. 8. Figs. 10, 11 and 12 are an edge, side and plan view,respectively, of the cam-block which actuates the sliding dogs. Fig. 13is a side view of one of the sliding dogs. Fig. 14 is a similar viewrespectively.

of one ofthe detachable face-plates with which said dogs are preferablyprovided. Figs. 15 and 16 are edge views of said dog and plate Figs. 17to 20, inclusive are detail views of the spring-actuated pawl by whichthe reversal of the movement of the tap is effected, and of the engaginglugs of the upper member. Figs. 21 and 22 are detail views illustratingthe application of my invention to a pipe tap.

The letter A designates the upper member of the tap-head, B the lowermember thereof, and O the tap proper. The memberA terminates at itsupper end in the tapering stem et adapted to be inserted in thespindle-socket of a drill-press, whereby the tap-head is operated in theusual manner. At its lower end the member A terminates in the outwardlyprojecting, annular flange a', and is provided with the downwardlyprojecting lugs o2, located at diametrically opposite points in saidflange. I prefer to make said lugs 0.2 as shown in Figs. 19 and 20, thatis to say, with a round stem 1 adapted to be driven into similarly vshaped holes in the member A and a head 2 having two of its sidesflattened to form bearing surfaces to engage the contact devices on thelower member, as hereinafter described. The member A is bored centrallyto form a socket to receive the stem of the lower member, and said boreat its upper end is increased in diameter to form the chamber 0.3,communicating1 with which chamber are two oppositely located holes a4.The lower member B is provided with the stem b adapted to snugly itwithin the bore of the upper member and to revolve freely therein, saidstem having a hole extending transverely therethrough, at its upper end,to receive a pin b of slightly less length than the diameter of chambera3 in member A, as shown, whereby said pin, while permitting arevolvingA and a limited vertical movement of the upper member upon thelower, will prevent the complete withdrawal of the latter from theformer. in alignment with the holes a4 the pin b can be readily insertedin and removed from the former. At the base of stem b the lower memberis enlarged to form hub b2 which has the rectangular openin g b3extending transversely therethrough, as shown in Fig. 8. Said lower Bybringing the hole in the stem b IOS) member` is also bored centrallyfrom its lower end to a point near the upper end of stem h, and iscounter-bored at its lower end to form the socket to receive the shank cof the tap C. I intend to employ aseries of taps, of various sizes, theshanks of which will be made of a proper size to iit the socket in themember B, and thereby avoid the use of the bushings described in my saidprevious patent. A screw b4 entering a tapped hole in the lower end ofmember B, and having its inner end adapted to enter a hole or recess inthe shank of the tap, as shown, may be employed to secure the tap in itssocket, or any suitable means for the purpose can be used. Within thebore of the lower member is located the cam-block b5 which, at its ends,is of such diameter as to cause it to snugly lit said bore, while beingfree to have longitudinal movement therein. A coil spring b@ located inthe upper end of the bore, normally retains said block in its lowestposition, while a screw 127 having its inner end adapted `to projectwithin the bore, as shown in Fig. l, serves to permit the insertion ofsaid block within the bore and to prevent its descent below said screwafter being so inserted. The central portion of the block b5 is removedupon opposite sides thereof, thus leaving a central, flattened stem 3uniting the heads Ll, and upon opposite sides of said stem are locatedoppositelyinclined ribs 5, whose planes bisect each other, see Figs. 10,ll and l2. lVithin the rectangular opening Z13 in hub b2 are located twosliding dogs b8 the length of which corresponds substantially with thediameter of said hub, which dogs are provided within their adjacentfaces with the oppositely inclined grooves 6, whose planes intersecteach other, as shown by broken lines in Figs. 2 and 3. The dogs hs areplaced within the hub with their grooves embracing the ribs 5 on theblock b5, and by the action of said ribs within said grooves, alongitudinal movement of said block within the bore of the lower memberwill cause a positive movement of said dogs, in opposite directionswithin the opening in hub b2, and will cause the outer ends of the dogsto project beyond the surface of the hub, as shown in Fig. 2, or to bewithdrawn within said hub, as shown in Fig. 3, as the block is moved inan upward or a downward direction. The parts just described are soarranged that spring b will normally retain the block b5 in its lowestposition, where its lower end rests upon screw 12"', and will retain thedogs bs in their outermost position, wherein their outer ends lie in theplane of revolution of the lugs a2 on member A, as shown in Figs. l and2. In

such normal position, therefore, a revolving movement imparted to theupper member of the head will be transmitted to the lower member thereofand in the same direction.

The means for automatically releasing the clutch preferably consists, asin myprevious patent, of a rod C centrally located within the tap C, insuch manner as to be capable of lengthwise movement therein, said rodhaving its lower end projecting beyond the end of the tap, and havingatits upper end ahead to prevent it from escaping downwardly through thetap. The operation of said releasing device will be fully apparent byreference to Figs. l and 2, in which it will bc seen that, as the tapapproaches the bottom of the hole in which it is operating, the rod Cgradually rises within the tap, carrying with it cam-block b5 andthrough the latter retracting dogs 58, un til the ends of the latter areentirely withdrawn Within hub b2, when the revolving movement of thelower member and of the tap will cease. The operator then reverses thedirection of movement of the spindle of the drill-press and of the uppermember of the head, and raises said parts uutil pin bat the upper end ofstem l) is brought into contact with the bottom of chamber a3 of memberA. In my previous patent, referred to, a fixed lug is located at thebottom of said chamber a3, which, by its contact with said pin b',transmits the reverse movement of the upper member to the lower member,and withdraws the tap from the hole. I have found, however, that acareless operator is liable to raise the upper member of the head beforereversing the movement thereof, and, the pin being thereby brought intocontact with said lug while it is still operating in the forwarddirection, and the tap being at the bottom of the hole, breakage of thetap or of some portion of the head is caused. In order to render itimpossible for the carelessness of an operator to thus cause injury tothe tap or head, I employ in lieu of said fixed lug the pawl a5, showndetached in Figs. 17 and 1S, which is preferably made round incross-section, whereby it is adapted to occupy a hole a bored in themember A, said hole extending from the bottom of said member to, andcommunicating with the chamber a3. I prefer to locate the hole a6 insuch position that a portion only of its area in cross-section will liewithin the plane of the bottom of chamber a3, as shown in Fig. 1, thusleaving only a portion of the upper end of the pawl a5 exposed to theaction of pin b. Pawl a5 is bored centrally from its lower end for aportion of its length, and at said lower end is provided with thetransverse slot a7. At its upper end said pawl is cut away to form therecess as having horizontal and vertical walls, and has said upper endbeveled at one side of said recess, as shown. The pawl is insertedwithin the hole a with its beveled surface, at its upper end, facing inthe direction of the forward revolving movement of member A, in whichposition it is retained by a screw a, which enters a tapped hole in theflange a of member A, and has its inner end reduced in diametersufficiently to enable it to loosely enter slot a7 in the pawl, and acoil spring al", which is located within the bore of the pawl and bearsat its ends against the upper end IOO IIO

IIS

496,420 l ,is

of said bore and said screw. The pawl isthus held in its highestposition by a yielding pressure, and, consequently, should' the operatorraise the upper member of the head before reversing its motion, thebeveled surface of the pawl will be brought into contact with pin b andthe pawl will be depressed and'will pass under the pin without exertingstrain upon the tap or any portion of the head. When the motion of theupper memberis reversed, however, the vertical wall of recess as willengage said pin b', and will revolve the lower member to withdraw thetap from the hole, in the same manner as the lug shown in my saidprevious patent. As the outer ends of the dogs bs are exposed toconsiderable wear upon their inner faces, or the faces which engage thelugs a2, I prefer to provide said dogs Awith bearing plates 7, see Figs.13 to 16 iuclusive, which plates will preferably have a smallhubprojecting from their rear sides to enter a recess in the face of thedog, and can be detachably secured to the dogs by bolts, or in anyconvenient manner. Said bearing plates can thus be renewed as often asmay be necessary, and at slight expense.

In Figs. 21 and 22 I have illustrated the application of my invention toa pipe-tap, in

which there is substituted for the ro'd C areleasing device composed ofa ring 8 sur-v against the end of lthe pipe as the tap approaches thebottom of the surface in the pipe which it is desired to operate upon,'astem 9 extending upwardly to andlying within a vertical groove in theshank of the tap, an inwardly extending arm 10 at the upper end of saidstem, occupyinga horizontal recess in the top of said shank, and anadjusting screw 11, entering a tapped hole in said arm,in the plane ofthe4 axis of the tap, whereby the distance between ring 8 and the lowerend of the tap can be accurately adjusted. As the device thusconstructed is moved upwardly, when ring 8 is brought into contact withthe end of the pipe, the upper end of screw 1l engages the lower end ofcam-block b5 and raises the latter, thus releasing the clutch andstopping the movement of the tap, as previously described. By using saiddevice in connection with a pipe-tap, an accurate gage to indicate uponthe Vtap itself the depth to which it is desired to operate within thetap, is provided, as well as means for automatically stopping the tap atthe proper point,as just described.

It willl be observed that the tap-head herein described is simple inconstruction, composed of few parts, and positive in all of its move#ments. 4

I do not wish to limit myself to the exact details of constructionherein shown `and'described, as it is obvious that modifications thereincan be made without departing from the spirit of my invention.

Having thus fully described my invention,

whatI claim, and desire to secure by Letters Patent, is-

1. The self-acting tap-head herein described consisting of an uppermember having at its lower end downwardly projecting lugs, and a lowermember having at its upper end radially movable dogs' adapted to beengaged by said lugs on the upper member and to be withdrawn from saidengagement, a vertically movable cam-block located within said lowermember and having positive engagement with said dogs, whereby movementof the former will be transmitted to the latter, a tap carried by saidlower member, and a gravity device carried by said tap in position 4toengage the materialin which the tap is operating as the latterapproaches the bottom of the surface to be tapped, said gravity deviceat its upper end abutting against said camblock, combined and operatingsubstantially as and for` the purpose described.

2, In a tap-head, an upper member having at lits lower end a centralsocket and two downwardly projecting lugs located at diamet! ricallyopposite points thereon, a lower member having at its upper end a'stemadapted to project within the socket in theupper member, and havingmounted within a transverse opening therein two sliding dogs adapted tobe engaged by said lugs on the upper member when said dogs are in theiroutermost positions, each of said dogs being provided with a cam-groovesubstantially as described, a cam-block located within a central bore insaid lower member and having :ribs

member B having stem b and having dogs bsV mounted to move transverselytherein, camblock b5 mounted in a central bore in said member B andengaging said dogs substantially in the manner described,I spring h6bearing against the upper end of said block,astop to support said blockat its lower end, tap C and rod C', combined and operatingsubstan-Vtially as set forth.

4. In a tap-head, member A having at its lower end a central bore andhaving at the upper end of said bore chamber a3, and a spring-'actuatedpawl projecting above the bottom of said chamber, member B havingl IIOstem b projecting within said chamber and having pin b' passedtransversely through theupper end of said stem, a positive clutchmechanism by which the revolving movement of said member A istransmitted to member B, and mechanism for automatically releasing saidclutch, combined an d operating substantially as and for the purpose setforth.

5. In the self-acting tap-head herein described, the combination withmember A having chamber a3, of pawl c5 located within hole a in saidmember and having its upper end projecting within said chamber, saidpaWl having its upper end beveled substantially as shown, and having theslot a7 at its lower end, spring al@ located Within a central bore insaid pawl, and screw a9 having its inner end inserted Within the slot insaid pawl, substantially as and for the purpose described.

6. In the self-acting tap-head herein described, member B having` thetransverse opening b3 therein and having dogs blocated l Within saidopening and adapted to have free movement therein, said dogs having theslots or grooves G therein, in combination with block b5 located Withina central bore in said member, said block being composed of the ends fiunited by stem 3, and having the inclined ribs 5 projecting fromopposite sides of said stem within the grooves in said dogs, spring h6,and stop-screw 67, arranged and 0perating substantially as described.

7. In a tap-head, member A having lugs @2in combination with member Bhaving dogs b5 and cam-block b5, said dogs being provided with thedetachable bearing-plates 7, substantially as described.

SANFORD D. LELAND.

itnessesr W. H. CHAPMAN, J. E. CHAPMAN.

